X射线荧光光谱熔片分析的校准曲线与玻璃片质量校正

Calibration curve and mass correction in fuse beads analysis of X-ray fluorescence spectrometry

在铁合金和铁矿石的X射线荧光光谱(XRF)熔片分析中,存在着样品直接灼烧和熔融质量变化不同产生的误差,常用的稀释比校正无法校正这种误差。实验提出在固定质量(体积)的熔剂中熔入系列被测组分的氧化物制备出质量(体积)相同的玻璃片标准系列,建立X射线荧光强度与玻璃片中被测组分体积浓度的函数曲线,使用样品玻璃片质量与校准曲线玻璃片的质量比校准分析结果,即质量校正代替稀释比校正。以纯物质(SiO_2、CaCO_3、Al_2O_3和Fe_2O_3)为标准,用选定的仪器工作条件,建立了硅钙合金分析用Si、Ca、Fe、Al质量分数对荧光强度的校准曲线,其线性相关系数分别为0.999 0、0.999 3、0.999 4、0.999 5。用标准样品考察了校准曲线的准确度。t检验结果表明,当玻璃片的质量变化较大时,不使用质量校正测量结果偏差较大,正确度差。

In fuse beads analysis of iron alloy and iron ore by X-ray fluorescence spectrometry,there was some error caused by the sample mass difference between direct ignition and fusion,and it could not be corrected by the conventional dilution ratio correction method.A series of tested oxide components were added into flux of fixed mass(volume)to prepare glass beads standard series with same mass(volume).The function curve was established between X-ray fluorescence intensity and volume concentration of tested component in glass beads.The analytical results were calibrated with the mass ratio of sample glass beads to that of calibration curve.In other words,the dilution ratio correction was replaced by mass correction.With pure substances(SiO2,CaCO3,Al2O3and Fe2O3)as standards,the calibration curve between the mass fraction and fluorescence intensity of Si,Ca,Fe and Al was established for analysis of calcium-silicon alloy under the selected instrumental working conditions.The linear correlation coefficient was0.9990,0.9993,0.9994and0.9995,respectively.The accuracy of calibration curve was verified with the certified reference material.The t test results showed that when the mass change of glass beads was large,the determination results without mass correction had great deviation with low accuracy.